Transcript Advanced FE-SEM: from nano-imaging to chemical and

Advanced FE-SEM:
from Nano-imaging to Chemical and Structural Analyses
Chi Ma
Division Analytical Facility
Division of Geological and Planetary Sciences, Caltech
[email protected]
http://www.gps.caltech.edu/facilities/analytical/
CSEM 2003
A high-resolution analytical scanning electron microscope (LEO 1550VP) was
installed in Sept 2002 at Caltech GPS Division Analytical Facility and became
available for campus-wide use in Dec 2002.
The new PC-based LEO 1550 SEM is a multipurpose state-of-the-art
instrument capable of SE, BSE, variable pressure SE, CL imaging, highresolution imaging (down to 1 nm), chemical and crystallographic analyses.
This is a field emission SEM which can operate at voltages ranging from 200 V
to 30 kV and at magnifications ranging from 20 x to 900 kx for a wide variety of
applications. The 1550 is equipped with two state-of-the-art accessories. The
first, an Oxford energy-dispersive X-ray spectrometer (EDS), can determine
and map the elemental distribution within a region or along a line, or perform a
quantitative chemical analysis of a point or region. The other accessory, a HKL
electron backscatter diffraction system (EBSD), can determine the crystal
structure and orientation of the sample at a specific point, and conduct
orientation mapping and phase identification at submicron scale.
The SEM was acquired and is supported in part by the MRSEC program of the
NSF under DMR-0080065.
CSEM 2003
The analytical SEM is having a wonderful impact on campus.
Since Dec 2002, about 85 users from 40 faculty research groups on
campus and JPL have used the SEM. They are from:
Material Sciences
EE, ME, CS
Applied Physics
Aero-engineering
Bio-engineering
Biology
Chemistry
Chemical Engineering
Physics
Geology
Geochemistry
Geophysics
Geobiology
CSEM 2004
Imaging Capabilities
(5 electron detectors)
• High resolution Imaging – InLens SE1
• Low Voltage Imaging (200V –
5kV) – better surface imaging due
to reduced beam penetration
• Compositional Contrast
Imaging - BSE
• Orientation Contrast Imaging –
FSE
• Variable Pressure SE Imaging
(3Pa-100Pa)
• Cathodoluminescence Imaging
• STEM imaging
CSEM 2003
Chemical Analysis - EDS
• Detector capable of detecting Be to U
• Quantitative EDS analysis Quantitative results with a relative
accuracy of better than 5% and detection
limits of better than 0.5% can be readily
obtained.
• X-ray mapping
Structural Analysis - EBSD
• Orientation mapping –
texture analysis
• Phase ID
CSEM 2003
Imaging, EDS and EBSD analyses at same time
CSEM 2003
BSE image showing chemical variation of micas
CL image of benitoite
STEM (left) and SE (right) images of borosilicate fibers